Drilling

What we drill

Drilling is the first and most decisive stage of drilling and blasting. Every blast hole is a small engineering decision: its diameter, depth, angle and position in the pattern are set by the rock mass, the bench geometry and the fragmentation the operation needs downstream. We drill production and development holes for surface and underground work, to a surveyed pattern that our blasting crews then charge and fire.

Drilling methods

• Top-hammer drilling — fast and economical on quarry benches and at shorter depths, where percussion energy is delivered from the surface.
• Down-the-hole (DTH) drilling — the hammer travels down the hole with the bit, keeping deep holes straight and transferring energy efficiently in hard, abrasive ground.
• Support and civil drilling — for road cuts, foundations and auxiliary work where a controlled hole is needed but not always a blast.

The choice between methods is driven by hole depth, rock hardness and the straightness the pattern demands. Deviation matters: a hole that wanders off line changes the burden and spacing at depth and degrades the blast result.

Pattern, diameter and depth

The drill pattern — burden and spacing — together with hole diameter and sub-drill depth control how evenly the charge is distributed through the rock. We set these to the geology and to the size the crusher and loaders want, not to a generic template. Accurate collaring and alignment keep the designed pattern intact all the way to the toe.

Where drilling is used

Blast-hole drilling supports quarries, open-pit and underground mines, tunnel headings, road construction and hydraulic works. It is the common first step across all of them.

How it fits the blast

Holes are surveyed and set out, drilled to the plan, then charged and initiated on a designed timing sequence. Good drilling makes a controlled, predictable blast possible — poor drilling cannot be corrected later with explosives. For the wider picture, see our guide to drilling and blasting and the overview of drilling methods.